JPH0564100A - Multiscreen television receiver - Google Patents

Abstract

PURPOSE:To always obtain a natural sub-screen by changing the rate of thinning out scanning lines in proportion to display methods when a sub-screen is inserted by a PIP method into a wide screen displaying an image of a current method. CONSTITUTION:The first generating means which generates the signal of the thinning-out rate 1/2 from a vertical synchronizing signal VD and a horizontal synchronizing signal HD and the second generating means which generates the signal of the thinning-out rate 2/3 from the vertical synchronizing signal VD and the horizontal synchronizing signal HD are provided. In addition, a selecting means 18 which selects either the output of the first generating means or that of the second generating means and a memory 11 which acts as an image compressor and compresses an image by thinning out video signals based upon the signal selected by the selecting means are provided. The selecting means 18 is changed over according to the methods for displaying the image of a current method on a wide screen, and scanning lines of a video signal are thinned out based upon the output of the selecting means 18, and so, the range of a sub-screen in the vertical direction comes to be constant. Thus, a natural sub-screen is obtained at always.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-screen television having a PIP (picture-in-picture) system capable of displaying a plurality of images on one monitor screen by simultaneously performing a plurality of screen processes. More particularly, the present invention relates to a multi-screen television receiver for displaying a screen of the current system on a screen of a high-definition system.

[0002]

2. Description of the Related Art Currently, NTSC television broadcasting is being carried out in Japan, and high-definition television broadcasting (high-definition) with a large screen and high definition is about to be started. In this high-definition, the aspect ratio of the screen is different from that of the current NTSC system, and a wide screen (aspect ratio 16: 9) receiver is adopted. Even with such a wide screen receiver, it is necessary to display an image with an aspect ratio of 4: 3 according to the current method.

When all the images having the aspect ratio of 4: 3 are displayed on the screen of the receiver having the aspect ratio of 16: 9, blank areas are formed on the left and right sides of the screen. In order to eliminate this blank area, an image with an aspect ratio of 4: 3 may be enlarged and displayed to fill the screen with an aspect ratio of 16: 9, but the upper and lower parts of the screen are cut off. This situation will be described with reference to FIG.

In FIG. 4, (a) shows an aspect ratio of 16:
This is a method of displaying all of the 4: 3 image on the screen of No. 9, and blank areas (hatched portions in the figure) occur on the left and right. (B) is a case where a 4: 3 image is displayed in an enlarged manner in order to eliminate this blank portion, but the upper and lower parts of the image (dotted lines in the figure) are cut.

When a PIP type sub-screen (aspect ratio 4: 3) is displayed on such a screen, the vertical range of the sub-screen in FIG. 4 (a) becomes "A", but in FIG. 4 (b). The vertical range of the sub-screen is "B"(B> A). This is because the sub-screen vertical thinning rate is the same,
The sub-screen of FIG. 4A has an aspect ratio of 4: 3, whereas the sub-screen of FIG. 4B does not have an aspect ratio of 4: 3. That is, the number of thinned scanning lines per screen is the same in both FIGS. 4A and 4B.
In (b), only the vertical direction of the sub-screen is enlarged as compared with FIG. 4 (a). Therefore, the compression ratios in the horizontal and vertical directions do not match, resulting in an unnatural screen.

[0006]

As described above, all the images of the current method are displayed on the wide screen and the PIP is displayed on this screen.
When the sub-screen according to the method is displayed, the aspect ratio of the sub-screen does not become 4: 3, so the compression ratios in the horizontal direction and the vertical direction do not match, resulting in an unnatural screen.

The present invention has been made in view of the above problems, and provides a natural sub-screen even when all the images of the current system are displayed on the wide screen and the sub-screen of the PIP system is displayed on this screen. With the goal.

[0008]

Means for Solving the Problems According to the means of the present invention, there is provided a first generating means for generating a signal having a thinning rate of 1/2 from a vertical synchronizing signal and a horizontal synchronizing signal, and a vertical synchronizing signal and a horizontal synchronizing signal. Second generation means for generating a signal with a thinning rate of 2/3, selection means for selecting one of the outputs of the first and second generation means, and an image based on the signal selected by this selection means By providing an image compression unit that performs image compression by thinning out signals, a natural sub-screen is always provided.

[0009]

The vertical range of the sub-screen is fixed by switching the selecting means according to the method of displaying the image of the current system on the wide screen and thinning the scanning lines of the video signal based on the output of the selecting means. become. This always provides a natural sub-screen.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. The video signal for the sub-screen is
/ D (analog / digital converter) 10
It is converted into a digital signal and supplied to the memory 11.
The memory 11 is also supplied with a thinning-out signal, and the thinning-out signal thins out the video signal and outputs it to the D / A (digital / analog converter) 12. The D / A 12 converts the input signal into an analog signal and outputs it from the output terminal 4.

The configuration of the above-described thinning-out signal generation circuit will be described. The vertical sync signal (VD) is transferred to F via the input terminal 3.
F (flip-flop) 13 to 16 clear terminals (C
L). Further, the horizontal synchronizing signal (HD) is supplied to the clock terminals (CK) of the FFs 13 to 16 via the input terminal 2. The output of FF13 is supplied to FF14, the output of FF14 is supplied to FF15, and FF1
The output of 5 is supplied to the EX-OR 17. Also FF
The output of 13 is also supplied to the EX-OR 17. Further, the inverted output of the FF15 is supplied to the FF13. The output of the EX-OR 17 is supplied to the selector 18.

On the other hand, the inverted output of the FF 16 is supplied to the input terminal of the FF 16, and the output of the FF 16 is supplied to the selector 18. A control signal is supplied to the selector 18, and one of the two input signals is selected and output. This output signal is the thinning signal described above.

Next, the operation of the circuit shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a timing chart in the circuit of FIG. In this figure, when the VD signal a rises, FF
The data of 13 to 16 are cleared of the data up to that time and output "L" from the output terminal Q of each FF. As a result, "H" is output from the inverting output terminal of FF15, and FF
13 is supplied to the input terminal D.

After the VD signal a rises, the HD signal b
The output c of the FF13 changes to "H" at the first rising edge of. And at the rising edge of the second clock, FF
The output d of 14 changes to "H", and the output e of the FF 15 changes to "H" at the rising edge of the third clock. At this time, the inverted output of FF15 becomes "L". Therefore, the output c of the FF 13 becomes "L" at the next clock. Thus, the FFs 13 to 15 form a shift register. The output f of the EX-OR 17 is "L" when both the signal c and the signal e are "H" or "L", and otherwise "H". Therefore, in the signal f, the ratio of "H" is 2 and the ratio of "L" is 1.

On the other hand, the FF 16 forms a binary counter, and its output is like the signal g. That is, FF1
From 6 the signal g in which the ratio of "H" and "L" are both 1
Is output.

By the way, when displaying an image of the current system on a wide screen, there are a method of displaying all the images (hereinafter referred to as a first method) and a method of displaying all images on the screen (hereinafter referred to as a second method and description). .. The control signal supplied to the selector 18 is a signal for switching the output signal of the selector 18 according to the first and second methods. Thereby, the signal g is selected when the first method is used, and the signal f is selected when the second method is used. When the thinning signal output from the selector 18 is "H",
The video signal is written in the memory 11, and when it is "L", it is skipped without being written.

FIG. 3 shows the configuration of the sub-screen when such a thinning signal is used. In this figure, (a) is the first
(B) is the display method according to the second method. Here, when the number of scanning lines S1 and S2 used for the sub-screen per field is obtained by the first and second methods, the equations (1) and (2) are obtained.

S1 = (525/2) × (2/3) = 525/3 (1) S2 = (525/2) × (1/2) = 525/4 (2) Thus, the thinning rate is changed By doing so, the vertical range of the sub-screen can be set to "A" in both the first and second methods.
This is because the distance between the scanning lines is the second as compared with the first method.
This is because the method is wide. Therefore, the compression ratios in the horizontal direction and the vertical direction of the sub-screen match, and a natural sub-screen can always be provided.

As described above, when an image of the current system is displayed on a wide screen and a sub screen is inserted in the screen by the PIP system, there are two types of display methods. It is possible to always provide a natural sub-screen by changing the thinning rate of the scanning lines according to this display method.

[0020]

As described above, when an image of the current method is displayed on a high-definition wide screen and a sub-screen is inserted in the screen by the PIP method, the thinning rate of scanning lines is changed according to the display method. It is possible to always provide a natural sub-screen.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a timing chart explaining the operation in FIG.

FIG. 3 is an explanatory diagram illustrating a sub-screen display method according to the present invention.

FIG. 4 is an explanatory diagram illustrating a conventional sub-screen display method.

[Explanation of symbols]

 10 ... A / D 11 ... Memory 12 ... D / A 13-16 ... FF 17 ... EX-OR 18 ... Selector

Claims (1)

[Claims] 1. A first generating means for generating a signal with a thinning rate of 1/2 from a vertical synchronizing signal and a horizontal synchronizing signal, and a signal with a thinning rate of 2/3 from a vertical synchronizing signal and a horizontal synchronizing signal. An image for performing image compression by thinning out a video signal based on a signal selected by the second generation unit, a selection unit that selects one of outputs of the first and second generation units, and a signal selected by the selection unit. A multi-screen television receiver comprising a compression means.